Balloon occlusion diameter and pressure measuring devices and methods of use

ABSTRACT

The invention provides a device having first and second balloons. Each of the first and second balloons communicates with an inflation lumen. A differential pressure gauge communicates with both inflation lumens. Each of the inflation lumens also communicates independently with a pump for inflating the balloon. The pressure gauge may include a shut-off valve for terminating inflation in the second balloon when the pressure within the first balloon exceeds the pressure in the second balloon. The pressure gauge may also include a pressure limiter. Methods of using the devices for measuring diameter and pressure of a balloon occluder deployed in a vessel or body cavity are disclosed.

FIELD OF THE INVENTION

The present invention relates generally to medical devices useful formeasuring the diameter and pressure of a balloon occluder deployedwithin a vessel. More particularly, the devices provide information onwhen the balloon occluder engages the vessel wall, diameter of thevessel wall, and force exerted on the vessel wall.

BACKGROUND OF THE INVENTION

Balloon occlusion devices are commonly deployed within a vessel duringvarious cardiovascular surgeries to provide isolation of blood flow.During conventional or minimally invasive surgeries, including coronaryartery bypass grafting, heart valve repair or replacement, septal defectrepair, pulmonary thrombectomy, atherectomy, aneurysm repair, aorticdissection repair and correction of congenital defects, for example,circulatory isolation of the coronary blood flow from the peripheralvascular system is often required to establish cardiopulmonary bypass.Instead of using the traditional methods of aortic clamping, a balloonoccluder is sometimes used to isolate blood flow in the aorta.Presently, balloon occluders are built to expand to the approximatelumenal diameter of the vessel, i.e., a balloon occluder with a smallerdiameter would be used for the carotid artery while larger balloons areused in the aorta. Balloon occlusion devices are also used in othernonvascular procedures, such as dilation of an esophageal stricture inpatients with achalasia, or dilation of an intra and/or extrahepaticbile duct in patients with biliary stenosis.

There are several disadvantages associated with the current methods ofinflating a balloon occluder in a vessel or body cavity. First, theoptimal size of the balloon occluder for occluding the lumen of thevessel or the body cavity is unknown and is usually estimated accordingto the average lumenal diameter. The vessel may be affected byatherosclerosis, and the actual lumenal diameter may be reduced. Second,as the balloon is inflated to occlude the lumen of the vessel or bodycavity, the point of contact of the perimeter of the balloon with thewall of the vessel or body cavity is uncertain. The operator can onlyestimate an acceptable level of wall distention. Third, the pressuregenerated by the expanded balloon on the wall of the vessel or bodycavity is unknown. Complications due to over-inflation of the balloonmay occur, including (1) atherosclerotic plaque rupture leading todistal embolization, (2) dissection of the vessel wall, (3)pseudoaneurysm formation due to subintimal hemorrhage, (4) aneurysmformation due to hyperextension and weakening of the vessel wall, (5)diverticulum formation due to weakening of the body tissue, and (6)vessel wall rupture or organ perforation.

New devices and methods are thus needed for balloon occlusion of avessel or body cavity, in order to provide information on the effectivediameter of the vessel or body cavity and allow an operator to optimallycontrol the inflation of the balloon without damage to the vessel wallor body tissue.

SUMMARY OF THE INVENTION

The invention provides devices and methods for controlling the inflationof balloon occlusion devices. One embodiment of the devices includesfirst and second balloons. The first balloon is adapted for insertioninto a patient's vessel or body cavity. The balloons may be elastomericor non-elastomeric balloons. Each of the two balloons communicates withan inflation lumen. Each inflation lumen communicates independently witha pump for inflating the balloon. Both lumens communicate with adifferential pressure gauge, which measures the pressure inside eachballoon, compares both pressures, and displays the information.

In another embodiment, the pumps are syringes, which are adapted forinfusion of air or fluid into the balloon. The syringes may operate intandem for inflating the balloons simultaneously. In still anotherembodiment, the pressure gauge includes a shut-off valve, operablyassociated with the second inflation lumen. The valve enables thepressure gauge to terminate inflation into the second lumen and balloonafter the pressure in the first balloon exceeds a certain threshold. Incertain embodiments, the gauge may include a pressure limiter whichlimits the pressure in the first balloon from exceeding a set threshold,thereby avoiding over-inflation of the first balloon inside the vesselor body cavity.

The invention provides methods for measuring the pressure of a balloonoccluder deployed in a patient's vessel or body cavity, e.g., bile duct.In a first method, using the devices described above, the first balloonis inserted through an incision into the lumen of a patient's vessel,e.g., aorta, or body cavity while maintaining the second balloon outsidethe patient's body. The first and second balloons are inflatedsimultaneously at the same rate of inflation by operating the pumps,which infuse air or fluid into the inflation lumens. The pressure withinthe first and second balloons are measured and compared by thedifferential pressure gauge, which comparison indicates when the firstballoon engages the lumenal wall of the vessel or body cavity. As thefirst balloon contacts the vessel wall, the pressure in the firstballoon rises disproportionately compared to the second balloon. Theoperator may then terminate inflation in the first balloon to avoidover-inflation.

In another method, when the pressure in the first balloon exceeds thepressure in the second balloon, the pressure gauge may activate theshut-off valve, thereby terminating the inflation of the second balloon.The gauge may be reset to measure the pressure within the first balloonand the atmosphere. In this way, any increase in the pressure in thefirst balloon is caused by the resistance of the vessel wall against theexpanding balloon. The less compliant the vessel, e.g., artery withatherosclerotic plaque, the higher the resistance of the vessel wall andthe higher the pressure registered in the pressure gauge. In theembodiment where the pressure gauge includes a pressure limiter, thelimiter may sound an alarm when the pressure in the first balloonexceeds a set threshold, thereby avoiding complications associated withover-inflation of the balloon occluder.

It will be understood that there are several advantages to using theballoon occlusion measuring devices and methods disclosed herein. Forexample, the devices (1) notify the physician when the balloon contactsa vessel wall, (2) provide information on the diameter of the vesselwall, (3) provide information on pressure exerted on the vessel wall,(4) can be employed in any vessel with or without stenosis, (5) can beemployed to occlude or dilate a body cavity, and (6) minimizecomplications associated with overinflation of the balloon occluder,i.e., wall rupture, dissection, pseudoaneurysm, and/or embolization.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an embodiment of the balloon occluder pressure measuringdevice according to the present invention.

FIG. 2A depicts a first balloon deployed in the aorta and a secondballoon outside the aorta.

FIG. 2B depicts the first balloon of FIG. 2A engaging the aortic wall.

FIG. 2 depicts a graph of the pressure differential between the firstand second balloons versus time.

DETAILED DESCRIPTION

The balloon occluder pressure measuring devices and methods are mostuseful in providing optimal inflation of a balloon occluder deployed ina patient's vessel, e.g., aortic occlusion for cardiopulmonary bypass,and in preventing complications associated with balloon over-inflation.It will be understood that the devices and methods may also be used toprovide optimal balloon inflation in occluding or dilating a patient'sbody cavity, e.g., the esophagus in patients with achalasia or the bileduct in biliary stenosis.

In FIG. 1, first balloon 10, which is inserted in the lumen of vessel100, communicates with inflation lumen 12. Second balloon 20, which isoutside the vessel, communicates with inflation lumen 22. Both lumens 12and 22 communicate with differential pressure gauge 50. Inflation lumens12 and 22 also communicate, respectively, with pumps 15 and 25, shownhere as syringes. Syringe 16 has plunger 15 disposed within lumen 14 ofthe syringe. Syringe 26 has plunger 25 disposed within lumen 24 of thesyringe. The syringes deliver air or fluid to the balloons through theirrespective inflation lumens. Proximal ends of plungers 15 and 25 may beactivated in tandem to simultaneously inflate balloons 10 and 20. Inuse, after balloon occluder 10 is deployed in vessel 100, balloons 10and 20 are inflated simultaneously, and at the same rate by advancingplungers 15 and 25 distally, forcing fluid or air through lumens 14 and24 to inflate balloons 10 and 20. The pressure differential betweenballoons 10 and 20 is measured and indicated on pressure gauge 50.

In FIG. 2A, balloon 10, having pressure P1 inside the balloon, isdeployed within vessel 100, and balloon 20, having pressure P2 insidethe balloon, is outside the vessel. As both balloons are inflated,balloon 10 engages the wall of vessel 100 as shown in FIG. 2B. Oncecontact is achieved with the vessel wall, the pressure within balloon 10rises disproportionatly to that of balloon 20, i.e., P1>>P2. Therelationship between the pressure differential for balloons 10 and 20(P1/P2) with inflation time (t) is illustrated in FIG. 2C. Time t1indicates when balloon 10 engages the vessel wall as depicted in FIG.2B. Before t1, the pressure differential between balloons 10 and 20remains relatively constant. After t1, the pressure differentialincreases due to resistance from the vessel wall.

In the embodiments where the pressure gauge includes a shut-off valveoperably associated with the second inflation lumen, inflation ofballoon 20 may be terminated when the first balloon makes contact withthe vessel wall. The gauge may be reset to measure the pressure withinballoon 10 and the atmosphere, so that P1/P2 reflects the resistancegenerated by the vessel wall. The less compliant the vessel, e.g.,artery with atherosclerosis plaque, the higher the resistance of thevessel wall. In this way, the devices provide the physician informationon (1) when the balloon occluder device contacts the vessel wall, (2)the effective lumenal diameter of the vessel, and (3) force exerted onthe vessel wall.

In still another embodiment, the pressure measuring device need notinclude a second balloon for pressure monitoring outside the body. Inthis embodiment, the physician carefully monitors the pressure gauge,noting when a significant pressure increase occurs (t=t1, when theballoon engages the vessel wall). Balloon inflation is then terminatedto avoid vessel hyperextension.

The length of the inflation lumen will generally be between 10 and 200centimeters, preferably approximately between 30 and 150 centimeters.The inner diameter of the inflation lumen will generally be between 0.05and 0.5 centimeters, preferably approximately between 0.1 and 0.3centimeters. The diameter of the expanded occluder will generally bebetween 0.3 and 2 centimeters, preferably approximately 0.5 and 1.0centimeters. The foregoing ranges are set forth solely for the purposeof illustrating typical device dimensions. The actual dimensions of adevice constructed according to the principles of the present inventionmay obviously vary outside of the listed ranges without departing fromthose basic principles.

Although the foregoing invention has, for the purposes of clarity andunderstanding, been described in some detail by way of illustration andexample, it will be obvious that certain changes and modifications maybe practiced which will still fall within the scope of the appendedclaims.

What is claimed is:
 1. A balloon occlusion inflation apparatus,comprising:a first balloon enclosing a chamber which communicates with afirst inflation lumen; a second balloon enclosing a chamber whichcommunicates with a second inflation lumen; a differential pressuregauge communicating with the first inflation lumen and the secondinflation lumen; a first pump communicating with the first inflationlumen; and a second pump communicating with the second inflation lumen.2. The apparatus of claim 1, wherein the first and second balloons areelastomeric.
 3. The apparatus of claim 1, wherein the first and secondballoons are non elastomeric.
 4. The apparatus of claim 1, wherein thefirst and second pumps are syringes.
 5. The apparatus of claim 4,wherein the syringes are tandem acting syringes.
 6. The apparatus ofclaim 1, wherein the pressure gauge includes a shut-off valve, operablyassociated with the second inflation lumen.
 7. The apparatus of claim 1,wherein the pressure gauge includes a pressure limiter.
 8. A method forocclusion of a vessel or body cavity, comprising the steps of:providinga balloon occlusion inflation apparatus comprising first and secondballoons communicating respectively with first and second inflationlumens, each inflation lumen communicating with a differential pressuregauge; inserting the first balloon into the lumen of a vessel or bodycavity while maintaining the second balloon outside of the vessel; andinflating the first and second balloons simultaneously and at the samerate of inflation, wherein the differential pressure gauge indicateswhen the first balloon engages the lumenal wall of the vessel or bodycavity.
 9. The method of claim 8, further comprising a first pumpcommunicating with the first inflation lumen and a second pumpcommunicating with the second inflation lumen.
 10. The method of claim9, wherein the first and second pumps are syringes.
 11. The method ofclaim 10, wherein the syringes are tandem acting syringes.
 12. Themethod of claim 8, wherein the first and second balloons areelastomeric.
 13. The method of claim 8, wherein the first and secondballoons are non-elastomeric.
 14. The method of claim 8, furthercomprising the step of terminating the inflation in the second balloonwhen the pressure in the first balloon exceeds the pressure in thesecond balloon.
 15. The method of claim 8, wherein the vessel is anartery.
 16. The method of claim 15, wherein the artery is the aorta. 17.The method of claim 8, wherein the body cavity is the esophagus.
 18. Themethod of claim 8, wherein the body cavity is the bile duct.